Methods, apparatuses and systems for predicting radio altimeter failure

ABSTRACT

Methods, apparatuses, and systems for predicting radio altimeter failures are provided. An example method may include determining a first plurality of altitude values associated with a first radio altimeter, determining a second plurality of altitude values associated with a second radio altimeter, calculating a first level feature based at least in part on the first plurality of altitude values and the second plurality of altitude values, and determining a radio altimeter failure indicator based at least in part on the first level feature.

FIELD OF THE INVENTION

The present disclosure relates generally to methods, apparatuses, andsystems associated with radio altimeter, and more particularly, tomethods, apparatuses, and systems for predicting radio altimeterfailure.

BACKGROUND

A “radio altimeter” or a “low range radio altimeter” is an electronicdevice that may measure the distance from one point to another point.For example, when a radio altimeter is equipped on an aircraft (such as,but is not limited to, airplanes, helicopters, airships, gliders, hotair balloons), the radio altimeter may measure the height of theaircraft above the terrain that is below the aircraft (i.e. the altitudeabove the terrain). In some examples, radio altimeters may play animportant role when the aircraft is approaching, at a low level, orduring nighttime by, for example, supplying the altitude information fordetermining the landing decision height (DH).

However, many systems and methods do not overcome technical challengesand difficulties associated with radio altimeter. For example, manysystems do not have the capability to detect radio altimeter failuresthat may, for example, return erroneous altitude readings. As anotherexample, many systems cannot predict whether a radio altimeter failureis likely to occur. In these systems, when a radio altimeter failuretakes place, the aircraft performance may be impacted, which may causeflight delays, cancellations, and/or high maintenance cost.

BRIEF SUMMARY

In accordance with various examples, an apparatus may be provided. Theapparatus may comprise at least one processor and at least onenon-transitory memory comprising program code. The at least onenon-transitory memory and the program code may be configured to, withthe at least one processor, cause the apparatus to at least: determine afirst plurality of altitude values associated with a first radioaltimeter; determine a second plurality of altitude values associatedwith a second radio altimeter; calculate a first level feature based atleast in part on the first plurality of altitude values and the secondplurality of altitude values; and determine a radio altimeter failureindicator based at least in part on the first level feature. In someexamples, the first level feature may comprise a plurality of mode valuedifferences.

In some examples, when calculating the first level feature, the at leastone non-transitory memory and the program code may be configured to,with the at least one processor, cause the apparatus to further:calculate a first plurality of mode values of the first plurality ofaltitude values; calculate a second plurality of mode values of thesecond plurality of altitude values; and calculate the plurality of modevalue differences between the first plurality of mode values and thesecond plurality of mode values.

In some examples, the first radio altimeter and the second radioaltimeter may be associated with an aircraft. In some examples, thefirst plurality of altitude values and the second plurality of altitudevalues may be associated with the aircraft in a cruising mode.

In some examples, when determining the radio altimeter failureindicator, the at least one non-transitory memory and the program codemay be configured to, with the at least one processor, cause theapparatus to further calculate a second level feature based at least inpart on the first level feature.

In some examples, when calculating the second level feature, the atleast one non-transitory memory and the program code may be configuredto, with the at least one processor, cause the apparatus to further:determine a plurality of time values associated with the plurality ofmode value differences; and select a subset of mode value differencesfrom the plurality of mode value differences. In some examples,corresponding time values associated with the subset of mode valuedifferences may satisfy a time value threshold.

In some examples, the at least one non-transitory memory and the programcode may be configured to, with the at least one processor, cause theapparatus to further: calculate a maximum difference value based on thesubset of mode value differences; and determine whether the maximumdifference value satisfies a maximum difference value threshold.

In some examples, the at least one non-transitory memory and the programcode may be configured to, with the at least one processor, cause theapparatus to further: in response to determining that the maximumdifference value does not satisfy the maximum difference valuethreshold, cause the radio altimeter failure indicator to indicate aradio altimeter failure.

In some examples, the at least one non-transitory memory and the programcode may be configured to, with the at least one processor, cause theapparatus to further: in response to determining that the maximumdifference value satisfies the maximum difference value threshold, causethe radio altimeter failure indicator to indicate no radio altimeterfailure.

In some examples, when calculating the second level feature, the atleast one non-transitory memory and the program code may be configuredto, with the at least one processor, cause the apparatus to further:calculate a mean value based on the subset of altitude valuedifferences; and determine whether the mean value satisfies a mean valuethreshold.

In some examples, when calculating the second level feature, the atleast one non-transitory memory and the program code may be configuredto, with the at least one processor, cause the apparatus to further:calculate a standard deviation value based on the subset of altitudevalue differences; and determine whether the standard deviation valuesatisfies a standard deviation value threshold.

In accordance with various examples, an apparatus may be provided. Theapparatus may comprise at least one processor and at least onenon-transitory memory comprising program code. The at least onenon-transitory memory and the program code may be configured to, withthe at least one processor, cause the apparatus to at least: determine afirst plurality of altitude values associated with a first radioaltimeter; determine a second plurality of altitude values associatedwith a second radio altimeter; calculate a first level feature based atleast in part on the first plurality of altitude values and the secondplurality of altitude values; and determine a radio altimeter failureindicator based at least in part on the first level feature. In someexamples, the first level feature may comprise a plurality of altitudevalue differences.

In some examples, the plurality of altitude value differences maycomprise a plurality of median value differences. In some examples, whencalculating the first level feature, the at least one non-transitorymemory and the program code may be configured to, with the at least oneprocessor, cause the apparatus to further: calculate a first pluralityof median values of the first plurality of altitude values; calculate asecond plurality of median values of the second plurality of altitudevalues; and calculate the plurality of median value differences betweenthe first plurality of median values and the second plurality of medianvalues.

In some examples, the plurality of altitude value differences maycomprise a plurality of mean value differences. In some examples, whencalculating the first level feature, the at least one non-transitorymemory and the program code may be configured to, with the at least oneprocessor, cause the apparatus to further: calculate a first pluralityof mean values of the first plurality of altitude values; calculate asecond plurality of mean values of the second plurality of altitudevalues; and calculate the plurality of mean value differences betweenthe first plurality of mean values and the second plurality of meanvalues.

In some examples, the plurality of altitude value differences maycomprise a plurality of standard deviation value differences. In someexamples, when calculating the first level feature, the at least onenon-transitory memory and the program code may be configured to, withthe at least one processor, cause the apparatus to further: calculate afirst plurality of standard deviation values of the first plurality ofaltitude values; calculate a second plurality of standard deviationvalues of the second plurality of altitude values; and calculate theplurality of standard deviation value differences between the firstplurality of standard deviation values and the second plurality ofstandard deviation values.

In accordance with various examples, a computer-implemented method maybe provided. The computer-implemented method may comprise: determining afirst plurality of altitude values associated with a first radioaltimeter; determining a second plurality of altitude values associatedwith a second radio altimeter; calculating a first level feature basedat least in part on the first plurality of altitude values and thesecond plurality of altitude values; and determining a radio altimeterfailure indicator based at least in part on the first level feature. Insome examples, the first level feature may comprise a plurality ofaltitude value differences.

In accordance with various examples, a computer program product may beprovided. The computer program product may comprise at least onenon-transitory computer-readable storage medium having computer-readableprogram code portions stored therein. The computer-readable program codeportions may comprise an executable portion that is configured to:determine a first plurality of altitude values associated with a firstradio altimeter; determine a second plurality of altitude valuesassociated with a second radio altimeter; calculate a first levelfeature based at least in part on the first plurality of altitude valuesand the second plurality of altitude values; and determine a radioaltimeter failure indicator based at least in part on the first levelfeature. In some examples, the first level feature comprises a pluralityof altitude value differences.

The foregoing illustrative summary, as well as other exemplaryobjectives and/or advantages of the disclosure, and the manner in whichthe same are accomplished, are further explained in the followingdetailed description and its accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The description of the illustrative embodiments may be read inconjunction with the accompanying figures. It will be appreciated that,for simplicity and clarity of illustration, elements illustrated in thefigures have not necessarily been drawn to scale, unless describedotherwise. For example, the dimensions of some of the elements may beexaggerated relative to other elements, unless described otherwise.Embodiments incorporating teachings of the present disclosure are shownand described with respect to the figures presented herein, in which:

FIG. 1 illustrates an example schematic diagram of an example system inaccordance with various embodiments of the present disclosure;

FIG. 2 illustrates an example block diagram of an example apparatus inaccordance with various embodiments of the present disclosure;

FIG. 3A illustrates an example plot diagram in accordance with variousembodiments of the present disclosure;

FIG. 3B illustrates an example plot diagram in accordance with variousembodiments of the present disclosure;

FIG. 3C illustrates an example plot diagram in accordance with variousembodiments of the present disclosure;

FIG. 4 illustrates an example flow diagram in accordance with variousembodiments of the present disclosure;

FIG. 5 illustrates an example flow diagram in accordance with variousembodiments of the present disclosure;

FIG. 6 illustrates an example flow diagram in accordance with variousembodiments of the present disclosure;

FIG. 7 illustrates an example flow diagram in accordance with variousembodiments of the present disclosure;

FIG. 8 illustrates an example flow diagram in accordance with variousembodiments of the present disclosure;

FIG. 9 illustrates an example flow diagram in accordance with variousembodiments of the present disclosure;

FIG. 10 illustrates an example flow diagram in accordance with variousembodiments of the present disclosure;

FIG. 11 illustrates an example flow diagram in accordance with variousembodiments of the present disclosure; and

FIG. 12 illustrates an example flow diagram in accordance with variousembodiments of the present disclosure.

DETAILED DESCRIPTION OF THE INVENTION

Some embodiments of the present disclosure will now be described morefully hereinafter with reference to the accompanying drawings, in whichsome, but not all embodiments of the disclosure are shown. Indeed, thesedisclosures may be embodied in many different forms and should not beconstrued as limited to the embodiments set forth herein; rather, theseembodiments are provided so that this disclosure will satisfy applicablelegal requirements. Like numbers refer to like elements throughout.

The phrases “in one embodiment,” “according to one embodiment,” “forexample,” “in some examples,” “as an example,” and the like generallymean that the particular feature, structure, or characteristic followingthe phrase may be included in at least one embodiment of the presentdisclosure, and may be included in more than one embodiment of thepresent disclosure (such phrases do not necessarily refer to the sameembodiment).

The word “example” or “exemplary” is used herein to mean “serving as anexample, instance, or illustration.” Any implementation described hereinas “example” or “exemplary” is not necessarily to be construed aspreferred or advantageous over other implementations.

If the specification states a component or feature “may,” “can,”“could,” “should,” “would,” “preferably,” “possibly,” “typically,”“optionally,” “for example,” “in some examples,” “often,” or “might” (orother such language) be included or have a characteristic, that aspecific component or feature is not required to be included or to havethe characteristic. Such component or feature may be optionally includedin some embodiments, or it may be excluded.

The term “circuitry” should be understood broadly to include hardwareand, in some embodiments, software for configuring the hardware. Withrespect to components of the apparatus, the term “circuitry” as usedherein should therefore be understood to include particular hardwareconfigured to perform the functions associated with the particularcircuitry as described herein. For example, in some embodiments,“circuitry” may include processing circuitry, storage media, networkinterfaces, input/output devices, and the like.

The term “electronically coupled,” “electronically coupling,”“electronically couple,” “in communication with,” “in electroniccommunication with,” or “connected” in the present disclosure refers totwo or more components (for example but not limited to, clientdevice(s), a data analytics system, database(s)) being connected throughwired means (for example but not limited to, wired Ethernet) and/orwireless means (for example but not limited to, Wi-Fi, Bluetooth,ZigBee), such that data and/or information may be transmitted to and/orreceived from these components.

The term “data analytics system” refers to a system or virtualenvironment that may be configured to generate data that may indicatethe likelihood of a radio altimeter failure. The data analytics systemmay take the form of one or more central servers disposed incommunication with one or more additional servers running softwareapplications, and having access to one or more databases storing digitalcontent items, application-related data, and/or the like. An exampledata analytics system is described at least in connection with FIG. 1herein.

The term “user” should be understood to refer to an individual, group ofindividuals, business, organization, and the like. The users referred toherein may access a data analytics system using client devices. The term“client device” refers to computer hardware and/or software that isconfigured to access the data analytics system. Client devices mayinclude, without limitation, smart phones, tablet computers, laptopcomputers, wearables, personal computers, enterprise computers, and thelike.

In some examples, data and information (such as electronic requests) maybe transmitted to and/or received from a data analytics system. Forexample, “radio altimeter failure prediction requests” may indicate arequest to generate a radio altimeter failure indicator, which mayindicate a likelihood of radio altimeter failure. In some examples,radio altimeter failure prediction requests may be transmitted to a dataanalytics system from a client device.

As described above, many systems and methods do not overcome technicalchallenges and difficulties associated with radio altimeters. Forexample, many systems lack the capability to detect or predict radioaltimeter failures.

In contrast, various examples in accordance with the present disclosuremay overcome these challenges and difficulties. In some examples, a dataanalytics system may be provided to analyze historical data associatedwith radio altimeters. The data analytics system may calculate a radioaltimeter failure indicator based on historical data associated with theradio altimeter. As such, various examples of the present disclosure mayimprove operations by enabling maintenance teams to better manage andallocate resources and/or by improving aircraft reliability. Variousexamples may also reduce operation cost by limiting the cancellationsand delays, minimizing spare part and supply requirements, and reducingtime for failure check and device maintenance.

Methods, apparatuses, and computer program products of the presentdisclosure may be embodied by any of a variety of devices. For example,the method, apparatus, and computer program product of an exampleembodiment may be embodied by a networked device (e.g., a data analyticssystem), such as a server or other network entity, configured tocommunicate with one or more devices, such as one or more clientdevices. Additionally, or alternatively, the computing device mayinclude fixed computing devices, such as a personal computer or acomputer workstation. Additionally, or alternatively, exampleembodiments may be embodied by any of a variety of mobile devices, suchas a portable digital assistant (PDA), mobile telephone, smartphone,laptop computer, tablet computer, wearable, or any combination of theaforementioned devices.

FIG. 1 illustrates an example system architecture 100 within whichembodiments of the present disclosure may operate. Users may access adata analytics system 115 via a communication network 103 using clientdevices 101A, 101B, . . . 101N.

The client devices 101A-101N may be any computing device as definedabove. Electronic data received by the data analytics system 115 fromthe client devices 101A-101N may be provided in various forms and viavarious methods. For example, the client devices 101A-101N may includedesktop computers, laptop computers, smartphones, netbooks, tabletcomputers, wearables, and the like. In some examples, one or more of theclient devices 101A-101N may each be assigned to a client deviceidentifier that uniquely identifies the client device. In some examples,the client device identifier may comprise an American Standard Code forInformation Interchange (ASCII) text, a pointer, a memory address, andthe like.

In embodiments where a client device of client devices 101A-101N is amobile device, such as a smart phone or tablet, the client device mayexecute an “app” to interact with the data analytics system 115. Suchapps are typically designed to execute on mobile devices, such astablets or smartphones. For example, an app may be provided thatexecutes on mobile device operating systems such as iOS®, Android®, orWindows®. These platforms typically provide frameworks that allow appsto communicate with one another and with particular hardware andsoftware components of mobile devices. For example, the mobile operatingsystems named above each provide frameworks for interacting withlocation services circuitry, wired and wireless network interfaces, usercontacts, and other applications. Communication with hardware andsoftware modules executing outside of the app is typically provided viaApplication Programming Interfaces (APIs) provided by the mobile deviceoperating system. In some examples, the app may provide a user interfacethat allows a user to interact with the data analytics system 115.

Additionally, or alternatively, the client devices 101A-101N mayinteract with the data analytics system 115 via a web browser.Additionally, or alternatively, the client devices 101A-101N may includevarious hardware or firmware designed to interface with the dataanalytics system 115.

The communication network 103 may include one or more wired or wirelesscommunication networks including, for example, a wired or wireless localarea network (LAN), personal area network (PAN), metropolitan areanetwork (MAN), wide area network (WAN), or the like, as well as anyhardware, software and/or firmware required to implement the one or morenetworks (such as, for example, network routers). For example, thecommunication network 103 may include general packet radio service(GPRS) network, Code Division Multiple Access 2000 (CDMA2000) network,Wideband Code Division Multiple Access (WCDMA) network, Global Systemfor Mobile Communications (GSM) network, Enhanced Data rates for GSMEvolution (EDGE) network, Time Division-Synchronous Code DivisionMultiple Access (TD-SCDMA) network, Long Term Evolution (LTE) network,High Speed Packet Access (HSPA) network, High-Speed Downlink PacketAccess (HSDPA) network, IEEE 802.11 (Wi-Fi), Wi-Fi Direct, and/or IEEE802.16 (WiMAX). Additionally, or alternatively, the communicationnetwork 103 may include a public network (such as the Internet), aprivate network (such as an intranet), or combinations thereof.

In some examples, the communication network 103 may utilize networkingprotocols including, but not limited to, Hypertext Transfer Protocol(HTTP) protocol, one or more Transmission Control Protocol/InternetProtocol (TCP/IP) based networking protocols, Near Field Communication(NFC) protocols, Bluetooth protocols, and/or ZigBee protocols. Forinstance, the networking protocol may be customized to suit the needs ofthe data analytics system 115. In some embodiments, the protocol may bea custom protocol of JSON objects sent via a Websocket channel. In someembodiments, the protocol may be JSON over RPC, JSON over REST/HTTP, andthe like.

Referring back to FIG. 1, the data analytics system 115 may be embodiedas a computing device described above. For example, the data analyticssystem 115 may comprise at least one processor and at least onenon-transitory memory storing computer program instructions. Thesecomputer program instructions may direct the data analytics system 115to function in a particular manner, such that the instructions stored inthe at least one non-transitory memory may produce an article ofmanufacture, the execution of which may implement embodiments of thepresent disclosure. As such, in some examples of the present disclosure,the data analytics system 115 may comprise a first level featurecalculator 117, a second level feature calculator 119, and/or a featureevaluator 121.

The first level feature calculator 117, the second level featurecalculator 119, and/or the feature evaluator 121 may be embodied inhardware means (such as circuitry or circuitries), software means (suchas computer program codes), or a combination of hardware means andsoftware means. In some examples, the first level feature calculator 117may be configured to calculate one or more first level features. In someexamples, the second level feature calculator 119 may be configured tocalculate one or more second level features. In some examples, thefeature evaluator 121 may be configured to determine a radio altimeterfailure indicator. An example diagram illustrating various components ofthe data analytics system 115 is illustrated and described in connectionwith at least FIG. 2.

It is noted that various components in the data analytics system 115 mayleverage the same computer or computing apparatus to perform operationsin accordance with examples of the present disclosure. For example, thefirst level feature calculator 117, the second level feature calculator119, and/or the feature evaluator 121 may leverage the same processor ormemory to perform these functions. In some examples, the first levelfeature calculator 117, the second level feature calculator 119, and/orthe feature evaluator 121 may utilize separated circuitries.

In various embodiments of the present disclosure, one or more electronicrequests may be sent to the data analytics system 115, including, butnot limited to, radio altimeter failure prediction requests. In someexamples, these electronic requests may be in the form of HTTP requests.In some examples, these electronic requests may be sent to the dataanalytics system 115 over the communication network 103 directly by aclient device of client devices 101A-101N. Additionally, oralternatively, the electronic requests may be sent to the data analyticssystem 115 via an intermediary.

In some examples, upon receiving the radio altimeter failure predictionrequests, the data analytics system 115 may generate one or more dataretrieval requests, and transmit the data retrieval requests to one ormore databases, such as, but not limited to, a flight database 105 asshown in FIG. 1. Based on the data received from the one or moredatabases, the data analytics system 115 may generate a radio altimeterfailure indicator, and may transmit the radio altimeter failureindicator to one or more of client devices 101A-101N.

Referring back to FIG. 1, the flight database 105 may be embodied as oneor more data storage devices such as a Network Attached Storage (NAS)device or devices, or as a separate server or servers. The flightdatabase 105 may include data and/or information accessible to the dataanalytics system 115 and/or the client devices 101A-101N.

In some examples, the flight database 105 may store data such as, but isnot limited to, flight data 107, which may be associated with one ormore flights of an aircraft. In some examples, the flight database 105may store data recorded in a quick access recorder (QAR) of theaircraft.

For example, the flight data 107 may include, but not limited to, timevalues 109, airground values 111, and/or altitude values 113A-113N. Insome examples, the airground values 111 may comprise an ASCII text, apointer, a memory address, and the like, which may indicate whether theaircraft is in a cruising mode at a given point of time. In someexamples, the altitude values 113A-113N may comprise an ASCII text, apointer, a memory address, and the like, which may indicate one or morealtitude values associated with one or more radio altimeters. In someexamples, the time values 109 may comprise an ASCII text, a pointer, amemory address, and the like, which may indicate a timestamp (forexample, date and time) of when an airground value of the airgroundvalues 111 or an altitude value of the altitude values 113A-113N wasrecorded. An example plot diagram illustrating various example airgroundvalues, altitude values, and time values is illustrated and described inconnection with at least FIG. 3A, FIG. 3B, and FIG. 3C.

It is noted that the flight database 105 may leverage the same computeror computing apparatus to perform the above-described operations. Forexample, the flight database 105 may be integrated within the dataanalytics system 115, such the flight database 105 may be part of thedata analytics system 115. In some examples, the flight database 105 andthe data analytics system 115 may utilize separated circuitries.

The data analytics system 115 of FIG. 1 may be embodied by one or morecomputing systems, such as apparatus 200 as shown in FIG. 2. Theapparatus 200 may include a processor 202, a memory 204, an input/outputcircuitry 206, and/or a communications circuitry 208. The apparatus 200may be configured to execute the operations described above with respectto FIG. 1 and below with respect to FIGS. 3-12.

Although these components are described with respect to functionallimitations, it should be understood that the particular implementationsnecessarily include the use of particular hardware. It should also beunderstood that certain of these components may include similar orcommon hardware. For example, two sets of circuitries may both leverageuse of the same processor, network interface, storage medium, or thelike to perform their associated functions, such that duplicate hardwareis not required for each set of circuitries.

In some embodiments, the processor 202 (and/or co-processor or any otherprocessing circuitry assisting or otherwise associated with theprocessor) may be in communication with the memory 204 via a bus forpassing information among components of the apparatus. The memory 204 isnon-transitory and may include, for example, one or more volatile and/ornon-volatile memories. In other words, for example, the memory 204 maybe an electronic storage device (e.g., a computer-readable storagemedium). The memory 204 may be configured to store information, data,content, applications, instructions, or the like for enabling theapparatus to carry out various functions in accordance with exampleembodiments of the present disclosure.

In the example as shown in FIG. 2, the memory 204 may store computerprogram instructions that may comprise a first level feature calculatormodule 210, a second level feature calculator module 212, and/or afeature evaluator module 214. When the first level feature calculatormodule 210 is executed by the processor 202, the apparatus 200 may beconfigured to calculate one or more first level features. When thesecond level feature calculator module 212 is executed by the processor202, the apparatus 200 may be configured to calculate one or more secondlevel features. When the feature evaluator module 214 is executed by theprocessor 202, the apparatus 200 may be configured to determine a radioaltimeter failure indicator.

Additionally, or alternatively, the apparatus 200 may include one ormore designated hardware configured for the first level featurecalculator module 210, the second level feature calculator module 212,and/or the feature evaluator module 214. For example, the apparatus 200may include a separate processor, specially configured FieldProgrammable Gate Array (FPGA), or Application Specific IntegratedCircuit (ASIC) that are configured to perform the functions of the firstlevel feature calculator module 210, the second level feature calculatormodule 212, and/or the feature evaluator module 214.

Referring back to FIG. 2, the processor 202 may be embodied in a numberof different ways and may, for example, include one or more processingdevices configured to perform independently. In some examples, theprocessor 202 may include one or more processors configured in tandemvia a bus to enable independent execution of instructions, pipelining,and/or multithreading. The use of the term “processor” or “processingcircuitry” may be understood to include a single core processor, amulti-core processor, multiple processors internal to the apparatus,and/or remote or “cloud” processors.

As described above, the processor 202 may be configured to executeinstructions stored in the memory 204 or otherwise accessible to theprocessor 202. In some preferred and non-limiting embodiments, theprocessor 202 may be configured to execute hard-coded functionalities.As such, whether configured by hardware or software methods, or by acombination thereof, the processor 202 may represent an entity (e.g.,physically embodied in circuitry) capable of performing operationsaccording to an embodiment of the present disclosure while configuredaccordingly. Alternatively, as another example, when the processor 202is embodied as an executor of software instructions, the instructionsmay specifically configure the processor 202 to perform the algorithmsand/or operations described herein when the instructions are executed.

The communications circuitry 208 may be any means such as a device orcircuitry embodied in either hardware or a combination of hardware andsoftware that is configured to receive and/or transmit data from/to anetwork and/or any other device, circuitry, or module in communicationwith the apparatus 200 (such as the client devices 101A-101N and/or theflight database 105 described above in connection with FIG. 1). In thisregard, the communications circuitry 208 may include, for example, anetwork interface for enabling communications with a wired or wirelesscommunication network (such as the communication network 103 describedabove in connection with FIG. 1). For example, the communicationscircuitry 208 may include one or more network interface cards, antennae,buses, switches, routers, modems, and supporting hardware and/orsoftware, or any other device suitable for enabling communications via anetwork. Additionally, or alternatively, the communications circuitry208 may include the circuitry for interacting with the antenna/antennaeto cause transmission of signals via the antenna/antennae or to handlereceipt of signals received via the antenna/antennae.

In some examples, the apparatus 200 may optionally include input/outputcircuitry 206 that may, in turn, be in communication with processor 202to provide output to the user and, in some embodiments, to receive anindication of a user input. The input/output circuitry 206 may comprisea user interface circuitry and may include a display, which may comprisea web user interface, a mobile application, a client device, a kiosk, orthe like. In some embodiments, the input/output circuitry 206 may alsoinclude a keyboard, a mouse, a joystick, a touch screen, touch areas,soft keys, a microphone, a speaker, or other input/output mechanisms.The processor and/or user interface circuitry comprising the processormay be configured to control one or more functions of one or more userinterface elements through computer program instructions (e.g., softwareand/or firmware) stored on a memory accessible to the processor (e.g.,memory 204, and/or the like).

It is also noted that all or some of the information discussed hereincan be based on data that is received, generated and/or maintained byone or more components of apparatus 200. In some embodiments, one ormore external systems (such as a remote cloud computing and/or datastorage system) may also be leveraged to provide at least some of thefunctionality discussed herein.

In some embodiments, other elements of the apparatus 200 may provide orsupplement the functionality of particular circuitry. For example, theprocessor 202 may provide processing functionality, the memory 204 mayprovide storage functionality, the communications circuitry 208 mayprovide network interface functionality, and the like. As will beappreciated, any such computer program instructions and/or other type ofcode may be loaded onto a computer, processor or other programmableapparatus's circuitry to produce a machine, such that the computer,processor or other programmable circuitry that execute the code on themachine creates the means for implementing various functions, includingthose described herein.

As described above and as will be appreciated based on this disclosure,embodiments of the present disclosure may be configured as methods,mobile devices, backend network devices, and the like. Accordingly,embodiments may comprise various means including entirely of hardware orany combination of software and hardware.

Referring now to FIG. 3A, FIG. 3B, and FIG. 3C, example plot diagramsare illustrated. In particular, example plot diagrams may show examplevalue sets (such as time values, airground values, and altitude values)associated with example flight data in an example flight database (suchas, but not limited to, the flight database 105 described above inconnection with FIG. 1). For example, each of the three plot diagramsmay indicate example relationships between example airground values andexample time values, as well as example relationships between examplealtitude values and example time values.

In FIG. 3A, the example plot diagram may comprise three portions: aportion 319, a portion 321, and a portion 323. The portion 319 mayillustrate example relationships between example airground values (asshown in the y-axis) and example time values (as shown in the x-axis)associated with an example aircraft. The portion 321 may illustrateexample relationships between example altitude values (as shown in they-axis) and example time values (as shown in the x-axis) associated witha first radio altimeter. The portion 323 may illustrate examplerelationships between example altitude values (as shown in the y-axis)and example time values (as shown in the x-axis) associated with asecond radio altimeter.

In FIG. 3B, the example plot diagram may comprise three portions: aportion 325, a portion 327, and a portion 329. The portion 325 mayillustrate example relationships between example airground values (asshown in the y-axis) and example time values (as shown in the x-axis)associated with an example aircraft. The portion 327 may illustrateexample relationships between example altitude values (as shown in they-axis) and example time values (as shown in the x-axis) associated witha first radio altimeter. The portion 329 may illustrate examplerelationships between example altitude values (as shown in the y-axis)and example time values (as shown in the x-axis) associated with asecond radio altimeter.

Referring now to FIG. 3C, the example plot diagram may comprise threeportions: a portion 301, a portion 303, and a portion 305. The portion301 may illustrate example relationships between example airgroundvalues (as shown in the y-axis) and example time values (as shown in thex-axis) associated with an example aircraft. The portion 303 mayillustrate example relationships between example altitude values (asshown in the y-axis) and example time values (as shown in the x-axis)associated with a first radio altimeter. The portion 305 may illustrateexample relationships between example altitude values (as shown in they-axis) and example time values (as shown in the x-axis) associated witha second radio altimeter.

In some examples, the time values, the airground values, and/or thealtitude values may be obtained from a quick access recorder (QAR)associated with an aircraft. In some examples, the time values, theairground values, and/or the altitude values may be obtained via othermeans.

As shown in the portion 301, the airground values may range from zero(0) to one (1). When the airground value equals to one (1) (as shown inthe y-axis), it may indicate that the aircraft has left the ground at agiven time point (as shown in the x-axis). When the airground valueequals to zero (0) (as shown in the y-axis), it may indicate that theaircraft is on the ground at a given time point (as shown in thex-axis).

In some examples, when airground value equals to one (1), it mayrepresent as an approximate indicator for determining that the aircraftis in a cruising mode. The term “cruising mode” refers to a flight phasewhere the aircraft may level after climbing to a set altitude and beforebeginning to descend. As an example, an airplane may carry out thefollowing modes in a chronological order during an example flight:takeoff mode (during which the airplane may leave the ground), climbingmode (during which the airplane may increase the altitude to apredetermined level), cruising mode (during which the airplane maymaintain or fluctuate around a predetermined altitude level), descendingmode (during which the airplane may decrease its altitude), and landingmode (during which the airplane may return to the ground). In thisexample, the airplane is in the cruising mode subsequent to the climbmode and prior to the descend mode.

In some examples, the climbing mode and/or the descending mode may takea short amount of time while the aircraft has left the ground. In otherwords, the cruising mode may take the most amount of time while theaircraft has left the ground (i.e. when the airground value equals toone (1)). As such, example systems and method may use the airgroundvalue as an approximate indicator for determining that the aircraft isin a cruising mode.

In some examples, the airplane may be in the cruising mode once duringevery flight. In this example, the airground values as shown in theportion 301 may be associated with multiple flights. In some examples,an aircraft may be in the cruising mode more than once during a flight.For example, an aircraft may change altitude during a flight in orderto, for example, avoid hash weather condition, avoid other air traffic,improve fuel consumption and/or a technical incident. In this example,an airplane may enter a second climbing mode after in a descending mode,and may enter a second cruising mode after the second climbing mode.

Referring back to FIG. 3C, the portion 303 and the portion 305 may eachbe associated with altitude values from a separate radio altimeterassociated with an aircraft. For example, the altitude values as shownin portion 303 may be recorded by a left low range radio altimeter,while the altitude values as shown in portion 305 may be recorded by aright low range radio altimeter. The portion 303 and the portion 305 mayshow example altitude values (in the y-axis) from the radio altimetersand their corresponding time points (in the x-axis).

While the examples as shown in FIG. 3A, FIG. 3B, and FIG. 3C mayillustrate altitude values from two radio altimeters, it is noted thatthe scope of the present disclosure is not limited to two radioaltimeters. In some examples, altitude values from less than two or morethan two radio altimeters may be utilized in accordance with variousexamples of the present disclosure.

In some examples, an example data analytics system may determine timevalues where the aircraft is in the cruising mode (for example, based onthe relationships between airground values and the time values as shownin the portion 301). In some examples, an example data analytics systemmay select altitude values that are associated with the time valuesindicating that the aircraft is in a cruising mode (for example, basedon the relationships between altitude values and the time values asshown in the portion 303 and in the portion 305).

For example, the data analytics system may determine that time valuerange 307 as shown in FIG. 3C is when the example aircraft is in thecruising mode during a flight, as the corresponding airground valuesequal to one (1) in the portion 301. The data analytics system mayselect altitude values 309 and 311 from portions 303 and 305,respectively, as time values correspond to these altitude values fallwithin the time value range 307.

As another example, the data analytics system may determine that timevalue range 313 as shown in FIG. 3C is when the example aircraft is inthe cruising mode during another flight, as the corresponding airgroundvalues equal to one (1) in the portion 301. The data analytics systemmay select altitude values 315 and 317 from portions 303 and 305,respectively, as time values correspond to these altitude values fallwithin the time value range 313.

In some examples, the data analytics system may determine a radioaltimeter failure indicator based at least in part on the altitudevalues. For example, FIG. 3A, FIG. 3B, and FIG. 3C may be associatedwith the same aircraft during different flights/dates: FIG. 3A may beassociated with the data recorded from May 19^(th) to May 21^(st), FIG.3B may be associated with data recorded from May 22^(nd) to May 24^(th),and FIG. 3C may be associated with data recorded from May 25^(th) andonward. In this example, portion 321 of FIG. 3A, portion 327 of FIG. 3B,and portion 303 of FIG. 3C may be associated with the same first radioaltimeter during different flights. Portion 323 of FIG. 3A, portion 329of FIG. 3B, and portion 305 of FIG. 3C may be associated with the samesecond radio altimeter during different flights.

In some examples, when there is no radio altimeter failure, the altitudevalues may remain stable when the aircraft is in a cruising mode. When aradio altimeter failure occurs, the altitude values may fluctuate orhave been fluctuating. For example, the time value range 307 of FIG. 3Cmay correspond to a time period when the radio altimeter may haveexperienced failure, as indicated by the fluctuations between thealtitude values 309 and 311. In some examples, the fluctuations maystart before the radio altimeter failure occurs. For example, as shownin FIG. 3A, the fluctuations may start as early as time period 331,which may be an indicator of the future radio altimeter failure as shownin FIG. 3C.

Referring now to FIG. 4 to FIG. 12, example methods in accordance withvarious embodiments of the present disclosure are illustrated. In someexamples, each block or step of the flowchart, and combinations ofblocks and steps in the flowchart, may be implemented by various meanssuch as hardware, circuitry and/or other devices associated withexecution of software including one or more computer programinstructions.

In some examples, one or more of the procedures described in the figuresmay be embodied by computer program instructions, which may be stored bya memory circuitry (such as a non-transitory memory) of an apparatusemploying an embodiment of the present disclosure and executed by aprocessing circuitry (such as a processor) of the apparatus. Thesecomputer program instructions may direct the apparatus to function in aparticular manner, such that the instructions stored in the memorycircuitry produce an article of manufacture, the execution of whichimplements the function specified in the flowchart block(s). Further,the apparatus may comprise one or more other components, such as, forexample, a communication circuitry and/or an input/output circuitry.Various components of the apparatus may be in electronic communicationbetween and/or among each other to transmit data to and/or receive datafrom each other.

In some examples, embodiments may take the form of a computer programproduct on a non-transitory computer-readable storage medium storingcomputer-readable program instructions (e.g. computer software). Anysuitable computer-readable storage medium may be utilized includingnon-transitory hard disks, CD-ROMs, flash memory, optical storagedevices, and/or magnetic storage devices.

Referring now to FIG. 4, an example method 400 in accordance with someembodiments of the present disclosure is illustrated. In particular, theexample method 400 may illustrate example embodiments of generating aradio altimeter failure indicator. In some examples, the method 400 maybe performed by a processing circuitry (for example, a processingcircuitry of the data analytics system 115 described in connection withFIG. 1 and/or the processor 202 of the apparatus 200 described inconnection with FIG. 2).

The method 400 starts at block 402.

At block 404, a processing circuitry (for example, a processingcircuitry of the data analytics system 115 described in connection withFIG. 1 and/or the processor 202 of the apparatus 200 described inconnection with FIG. 2) may determine a first plurality of altitudevalues associated with a first radio altimeter. In some examples, theprocessing circuitry may determine the first plurality of altitudevalues from a database, such as, but not limited to, the flight database105 as shown in FIG. 1.

For example, the processing circuitry may receive a radio altimeterfailure prediction request from one of the client devices 101A-101N asshown in FIG. 1. The radio altimeter failure prediction request maycomprise a request to generate a radio altimeter failure indicator,which may indicate the likelihood that a radio altimeter may fail. Insome examples, the radio altimeter failure prediction request maycomprise an identifier associated with the radio altimeter and/or theaircraft. Upon receiving the radio altimeter failure prediction request,the processing circuitry may transmit a data retrieval request (whichmay comprise, for example, an identifier associated with the radioaltimeter and/or the aircraft) to the flight database 105. Theprocessing circuitry may receive flight data associated with the radioaltimeter and/or the aircraft from the flight database 105. For example,the flight data may comprise a plurality of altitude values that wererecorded by the radio altimeter.

In some examples, the plurality of altitude values may be associatedwith the aircraft in a cruising mode. As described above in connectionwith FIG. 3A, FIG. 3B, and/or FIG. 3C, each altitude value and/orairground value may have a corresponding time value, and each time valuemay be a timestamp indicating the time each altitude value and/orairground value was recorded. For example, upon receiving the radioaltimeter failure prediction request, the processing circuitry mayretrieve a plurality of airground values associated with the radioaltimeter and/or the aircraft (from, for example, the flight database105 as described above in connection with FIG. 1). The processingcircuitry may determine a range of time values where the correspondingairground value equals to one (1). Based on the range of time values,the processing circuitry may select corresponding altitude values thatare associated with the aircraft in a cruising mode, similar to thosedescribed above in connection with FIG. 3A, FIG. 3B, and/or FIG. 3C.

Additionally, or alternatively, the processing circuitry may selectaltitude values that associated with the aircraft not in a cruising mode(for example, in a climbing mode and/or a descending mode).

At block 406, a processing circuitry (for example, a processingcircuitry of the data analytics system 115 described in connection withFIG. 1 and/or the processor 202 of the apparatus 200 described inconnection with FIG. 2) may determine a second plurality of altitudevalues associated with a second radio altimeter.

Similar to those described above in connection with block 404, in someexamples, the processing circuitry may determine the second plurality ofaltitude values from a database, such as, but not limited to, the flightdatabase 105 as shown in FIG. 1. In some examples, the plurality ofaltitude values may be associated with the aircraft in a cruising modeas described above.

While the example as shown in FIG. 4 may illustrate two sets of altitudevalues, the scope of the present disclosure is not limited to only twosets. In some examples, the processing circuitry may determineadditional set(s) of altitude values from one or more additional radioaltimeters. In some examples, the processing circuitry may determineless than two sets of altitude values.

At block 408, a processing circuitry (for example, a processingcircuitry of the data analytics system 115 described in connection withFIG. 1 and/or the processor 202 of the apparatus 200 described inconnection with FIG. 2) may calculate a first level feature.

In some examples, the first level feature may be a mathematical valuethat may be calculated by the processing circuitry based at least inpart on, for example, but not limited to, the first plurality ofaltitude values determined at block 404 and the second plurality ofaltitude values determined at block 406.

In some examples, the first level feature may comprise a plurality ofaltitude value differences. For example, the first level feature maycomprise a plurality of mode value differences, a plurality of medianvalue differences, a plurality of mean value differences, and/or aplurality of standard deviation value differences. Example details aredescribed in connection with at least FIG. 5, FIG. 6, FIG. 7, and FIG.8.

Referring back to FIG. 4, a processing circuitry (for example, aprocessing circuitry of the data analytics system 115 described inconnection with FIG. 1 and/or the processor 202 of the apparatus 200described in connection with FIG. 2) may determine a radio altimeterfailure indicator at block 410.

In some examples, the radio altimeter failure indicator may be in theform of a flag value that may indicate whether there is or will likelybe a radio altimeter failure. For example, when the radio altimeterfailure indicator is set to TRUE, it may indicate that there is or willlikely be a radio altimeter failure. When the radio altimeter failureindicator is set to FALSE, it may indicate that there is no radioaltimeter failure (or that there is not going to be a radio altimeterfailure).

In some examples, the radio altimeter failure indicator may be in theform of a percentage value, which may indicate the likelihood that theradio altimeter may fail. For example, when the radio altimeter failureindicator is set to 0%, it may indicate that the radio altimeter willnot fail. In some examples, the higher the percentage value of the radioaltimeter failure indicator, the more likely that the radio altimetermay fail (as predicted by the processing circuitry).

In some examples, the radio altimeter failure indicator may be in otherforms.

In some examples, the processing circuitry may determine a radioaltimeter failure indicator based at least in part on the first levelfeature. For example, the processing circuitry may calculate a secondlevel feature based at least in part on the first level feature. Basedon the second level feature, the processing circuitry may set the valueof the radio altimeter failure indicator accordingly. As describedabove, altitude values may be recorded when the aircraft is in acruising mode. In this example, the second level feature may indicatethe trend(s) of altitude values recorded by the radio altimeter when theaircraft is cruising. Based on the trend(s), the radio altimeter failureindicator may be determined. Example details are described in connectionwith at least FIG. 9, FIG. 10, FIG. 11, and FIG. 12.

The method 400 ends at block 412.

Referring now to FIG. 5, FIG. 6, FIG. 7, and FIG. 8, example methods inaccordance with some embodiments of the present disclosure areillustrated. In particular, these example methods may illustrate exampleembodiments of calculating a first level feature (which may be relatedto, for example, block 408 of FIG. 4 as described above).

Referring now to FIG. 5, an example method 500 in accordance with someembodiments of the present disclosure is illustrated. In particular, theexample method 500 may illustrate example embodiments of calculating amode value difference as an altitude value difference for the firstlevel feature. In some examples, the method 500 may be performed by aprocessing circuitry (for example, a processing circuitry of the dataanalytics system 115 described in connection with FIG. 1 and/or theprocessor 202 of the apparatus 200 described in connection with FIG. 2).

The method 500 may start from block A. Referring back to FIG. 4, block Amay be subsequent to determining a first plurality of altitude values(block 404) and determining a second plurality of altitude values (block406).

At block 501, a processing circuitry (for example, a processingcircuitry of the data analytics system 115 described in connection withFIG. 1 and/or the processor 202 of the apparatus 200 described inconnection with FIG. 2) may calculate a first mode value of the firstplurality of altitude values. In some examples, the first plurality ofaltitude values may be determined in accordance with block 404 describedabove in connection with FIG. 4.

The “mode value” of a data set refers to a value that appears the mostoften in the data set. As a non-limiting example, if the followingexample data set D1 represents the first plurality of altitude values:D1={1800,1802,1800,1810,1812}The processing circuitry may determine that the first mode value is1800, as 1800 appears the most often in the above example data set D1.

In some examples, when there are two or more modes in the firstplurality of altitude values, the processing circuitry may choose thehighest value among the two or more modes as the first mode value. Insome examples, the processing circuitry may choose the lowest valueamong the two or more modes as the first mode value.

In some examples, when there is no mode from the first plurality ofaltitude values, the processing circuitry may calculate the median valueor the mean value as the first mode value, details of which aredescribed in connection with at least FIG. 6 and FIG. 7 herein.

At block 503, a processing circuitry (for example, a processingcircuitry of the data analytics system 115 described in connection withFIG. 1 and/or the processor 202 of the apparatus 200 described inconnection with FIG. 2) may calculate a second mode value of the secondplurality of altitude values.

In some examples, the second plurality of altitude values may bedetermined in accordance with block 406 described above in connectionwith FIG. 4. In some examples, the second mode value may be calculatedby the processing circuitry similar to those described above inconnection with block 501.

At block 505, a processing circuitry (for example, a processingcircuitry of the data analytics system 115 described in connection withFIG. 1 and/or the processor 202 of the apparatus 200 described inconnection with FIG. 2) may calculate a mode value difference betweenthe first mode value and the second mode value. For example, theprocessing circuitry may calculate the mode value difference based onthe following equation:ΔMo=Mo ₁ −Mo ₂where ΔMo is the mode value difference, Mo₁ is the first mode valuecalculated at block 501, and Mo₂ is the second mode value calculated atblock 503. In some examples, the mode value difference may be anabsolute value, which may be calculated based on the following equation:ΔMo=|Mo ₁ −Mo ₂|In some examples, the mode value difference calculated at block 505 maybe one of the plurality of altitude value differences of the first levelfeature.

Subsequent to block 505, the method 500 may return to block B. As shownin FIG. 4, block B may be prior to determining a radio altimeter failureindicator based at least in part on the first level feature at block410. The plurality of altitude value differences of the first levelfeature may comprise at least one mode value difference as described inconnection with FIG. 5.

While the example as shown in FIG. 5 illustrates generating one modevalue difference, it is noted that the method 500 as descried in FIG. 5may be repeated by a processing circuitry on a plurality of first modevalues and a plurality of second mode values to generate a plurality ofmode value differences.

For example, the processing circuitry may generate a mode valuedifference for each flight. Referring to the example as shown in FIG.3C, the processing circuitry may generate a first mode value Mo₁ ¹ basedon the altitude values 309 and a second mode value Mo₂ ¹ based on thealtitude values 311, and may calculate a first mode value differenceΔMo¹ based on Mo₁ ¹ and Mo₂ ¹. The processing circuitry may alsogenerate another first mode value Mo₁ ² based on the altitude values 315and another second mode value Mo₂ ² based on the altitude values 317,and may calculate a second mode value difference ΔMo² based on Mo₁ ² andMo₂ ².

In some examples, the processing circuitry may utilize the plurality ofmode value differences to determine the radio altimeter failureindicator, details of which are described in connection with at leastFIG. 9, FIG. 10, FIG. 11, and FIG. 12.

Referring now to FIG. 6, an example method 600 in accordance with someembodiments of the present disclosure is illustrated. In particular, theexample method 600 may illustrate example embodiments of calculating amedian value difference as an altitude value difference for the firstlevel feature. In some examples, the method 600 may be performed by aprocessing circuitry (for example, a processing circuitry of the dataanalytics system 115 described in connection with FIG. 1 and/or theprocessor 202 of the apparatus 200 described in connection with FIG. 2).

The method 600 may start from block A. Referring back to FIG. 4, block Amay be subsequent to determining a first plurality of altitude values(block 404) and determining a second plurality of altitude values (block406).

At block 602, a processing circuitry (for example, a processingcircuitry of the data analytics system 115 described in connection withFIG. 1 and/or the processor 202 of the apparatus 200 described inconnection with FIG. 2) may calculate a first median value of the firstplurality of altitude values. In some examples, the first plurality ofaltitude values may be determined in accordance with block 404 describedabove in connection with FIG. 4.

The “median value” of a data set refers to a value in the data set thatseparates the higher half from the lower half. As a non-limitingexample, if the following example data set D1 represents the firstplurality of altitude values:D1={1800,1802,1800,1810,1812}The processing circuitry may determine that the first median value is1802, as D1 contains five values and 1802 is the third value (middle) ifthe values are arranged from the lowest to the highest (or from thehighest to the lowest).

In some examples, when there is an even number of values in the firstplurality of altitude values, the processing circuitry may calculate themedian value as the mean of the two middle values.

At block 604, a processing circuitry (for example, a processingcircuitry of the data analytics system 115 described in connection withFIG. 1 and/or the processor 202 of the apparatus 200 described inconnection with FIG. 2) may calculate a second median value of thesecond plurality of altitude values.

In some examples, the second plurality of altitude values may bedetermined in accordance with block 406 described above in connectionwith FIG. 4. In some examples, the second median value may be calculatedby the processing circuitry similar to those described above inconnection with block 602.

At block 606, a processing circuitry (for example, a processingcircuitry of the data analytics system 115 described in connection withFIG. 1 and/or the processor 202 of the apparatus 200 described inconnection with FIG. 2) may calculate a median value difference betweenthe first median value and the second median value.

At block 606, a processing circuitry (for example, a processingcircuitry of the data analytics system 115 described in connection withFIG. 1 and/or the processor 202 of the apparatus 200 described inconnection with FIG. 2) may calculate a median value difference betweenthe first median value and the second median value. For example, theprocessing circuitry may calculate the median value difference based onthe following equation:Δ{tilde over (x)}={tilde over (x)} ₁ −{tilde over (x)} ₂where Δ{tilde over (x)} is the median value difference, {tilde over(x)}₁ is the first median value calculated at block 602, and {tilde over(x)}₂ is the second median value calculated at block 604. In someexamples, the median value difference may be an absolute value, whichmay be calculated based on the following equation:Δ{tilde over (x)}=|{tilde over (x)} ₁ −{tilde over (x)} ₂|In some examples, the median value difference calculated at block 606may be one of the plurality of altitude value differences of the firstlevel feature.

Subsequent to block 606, the method 600 may return to block B. Referringback to FIG. 4, block B may be prior to determining a radio altimeterfailure indicator based at least in part on the first level feature atblock 410. The plurality of altitude value differences of the firstlevel feature may comprise at least one median value difference asdescribed in connection with FIG. 6.

While the example as shown in FIG. 6 may illustrate generating onemedian value difference, it is noted that the method 600 as descried inFIG. 6 may be repeated by a processing circuitry on a plurality of firstmedian values and a plurality of second median values to generate aplurality of median value differences.

For example, the processing circuitry may generate a median valuedifference for each flight. Referring to the example as shown in FIG.3C, the processing circuitry may generate a first median value {tildeover (x)}₁ ¹ based on the altitude values 309 and a second median value{tilde over (x)}₂ ¹ based on the altitude values 311, and may calculatea first median value difference Δ{tilde over (x)}¹ based on {tilde over(x)}₁ ¹ and {tilde over (x)}₂ ¹. The processing circuitry may alsogenerate another first median value {tilde over (x)}₁ ² based on thealtitude values 315 and another second median value {tilde over (x)}₂ ²based on the altitude values 317, and may calculate a second medianvalue difference Δ{tilde over (x)}² based on {tilde over (x)}₁ ² and{tilde over (x)}₂ ².

In some examples, the processing circuitry may utilize the plurality ofmedian value differences to determine the radio altimeter failureindicator, details of which are described in connection with at leastFIG. 9, FIG. 10, FIG. 11, and FIG. 12.

Referring now to FIG. 7, an example method 700 in accordance with someembodiments of the present disclosure is illustrated. In particular, theexample method 700 may illustrate example embodiments of calculating amean value difference as an altitude value difference for the firstlevel feature. In some examples, the method 700 may be performed by aprocessing circuitry (for example, a processing circuitry of the dataanalytics system 115 described in connection with FIG. 1 and/or theprocessor 202 of the apparatus 200 described in connection with FIG. 2).

The method 700 may start from block A. Referring back to FIG. 4, block Amay be subsequent to determining a first plurality of altitude values(block 404) and determining a second plurality of altitude values (block406).

At block 701, a processing circuitry (for example, a processingcircuitry of the data analytics system 115 described in connection withFIG. 1 and/or the processor 202 of the apparatus 200 described inconnection with FIG. 2) may calculate a first mean value of the firstplurality of altitude values. In some examples, the first plurality ofaltitude values may be determined in accordance with block 404 describedabove in connection with FIG. 4.

The “mean value” of a data set may be calculated based on dividing thesum of values in the data set by the number of values. As a non-limitingexample, if the following example data set D1 represents the firstplurality of altitude values:D1={1800,1802,1800,1810,1812}The processing circuitry may determine that the first mean value is1804.8, which may be calculated based on the following:

$\frac{1800 + 1802 + 1800 + 1810 + 1812}{5} = 1804.8$

At block 703, a processing circuitry (for example, a processingcircuitry of the data analytics system 115 described in connection withFIG. 1 and/or the processor 202 of the apparatus 200 described inconnection with FIG. 2) may calculate a second mean value of the secondplurality of altitude values.

In some examples, the second plurality of altitude values may bedetermined in accordance with block 406 described above in connectionwith FIG. 4. In some examples, the second mean value may be calculatedby the processing circuitry similar to those described above inconnection with block 701.

At block 705, a processing circuitry (for example, a processingcircuitry of the data analytics system 115 described in connection withFIG. 1 and/or the processor 202 of the apparatus 200 described inconnection with FIG. 2) may calculate a mean value difference betweenthe first mean value and the second mean value. For example, theprocessing circuitry may calculate the mean value difference based onthe following equation:Δ x=x ₁ −x ₂where Δx is the mean value difference, x₁ is the first mean valuecalculated at block 701, and x ₂ is the second mean value calculated atblock 703. In some examples, the mean value difference may be anabsolute value, which may be calculated based on the following equation:Δ x=|x ₁ −x ₂|In some examples, the mean value difference calculated at block 705 maybe one of the plurality of altitude value differences of the first levelfeature.

Subsequent to block 705, the method 700 may return to block B. Referringback to FIG. 4, block B may be prior to determining a radio altimeterfailure indicator based at least in part on the first level feature atblock 410. The plurality of altitude value differences of the firstlevel feature may comprise at least one mean value difference asdescribed in connection with FIG. 7.

While the example as shown in FIG. 7 may illustrate generating one meanvalue difference, it is noted that the method 700 as descried in FIG. 7may be repeated by a processing circuitry on a plurality of first meanvalues and a plurality of second mean values to generate a plurality ofmean value differences.

For example, the processing circuitry may generate a mean valuedifference for each flight. Referring to the example as shown in FIG.3C, the processing circuitry may generate a first mean value x ₁ ¹ basedon the altitude values 309 and a second mean value x ₂ ¹ based on thealtitude values 311, and may calculate a first mean value difference Δx¹ based on x ₁ ¹ and x ₂ ¹. The processing circuitry may also generateanother first mean value x ₁ ² based on the altitude values 315 andanother second mean value x ₂ ² based on the altitude values 317, andmay calculate a second mean value difference Δx ² based on x ₁ ² and x ₂².

In some examples, the processing circuitry may utilize the plurality ofmean value differences to determine the radio altimeter failureindicator, details of which are described in connection with at leastFIG. 9, FIG. 10, FIG. 11, and FIG. 12.

Referring now to FIG. 8, an example method 800 in accordance with someembodiments of the present disclosure is illustrated. In particular, theexample method 800 may illustrate example embodiments of calculating astandard deviation value difference as an altitude value difference forthe first level feature. In some examples, the method 800 may beperformed by a processing circuitry (for example, a processing circuitryof the data analytics system 115 described in connection with FIG. 1and/or the processor 202 of the apparatus 200 described in connectionwith FIG. 2).

The method 800 may start from block A. Referring back to FIG. 4, block Amay be subsequent to determining a first plurality of altitude values(block 404) and determining a second plurality of altitude values (block406).

At block 802, a processing circuitry (for example, a processingcircuitry of the data analytics system 115 described in connection withFIG. 1 and/or the processor 202 of the apparatus 200 described inconnection with FIG. 2) may calculate a first standard deviation valueof the first plurality of altitude values. In some examples, the firstplurality of altitude values may be determined in accordance with block404 described above in connection with FIG. 4.

The “standard deviation value” refers to a number that may indicate howvalues in a data set may spread out from the mean value. As anon-limiting example, if the following example data set D1 representsthe first plurality of altitude values:D1={1800,1802,1800,1810,1812}The processing circuitry may determine that the first standard deviationvalue is 5, which may be calculated based on the following:

(1800 − 1804.8)² + (1802 − 1804.8)² + (1800 − 1804.8)² + (1810 − 1804.8)² + (1812 − 1804.8)² = 132.8$\mspace{76mu}{\sqrt{\frac{132.8}{5}} \approx 5}$

At block 804, a processing circuitry (for example, a processingcircuitry of the data analytics system 115 described in connection withFIG. 1 and/or the processor 202 of the apparatus 200 described inconnection with FIG. 2) may calculate a second standard deviation valueof the second plurality of altitude values.

In some examples, the second plurality of altitude values may bedetermined in accordance with block 406 described above in connectionwith FIG. 4. In some examples, the second standard deviation value maybe calculated by the processing circuitry similar to those describedabove in connection with block 802.

At block 806, a processing circuitry (for example, a processingcircuitry of the data analytics system 115 described in connection withFIG. 1 and/or the processor 202 of the apparatus 200 described inconnection with FIG. 2) may calculate a standard deviation valuedifference between the first standard deviation value and the secondstandard deviation value. For example, the processing circuitry maycalculate the standard deviation value difference based on the followingequation:Δσ=σ₁−σ₂where Δσ is the standard deviation value difference, σ₁ is the firststandard deviation value calculated at block 802, and σ₂ is the secondstandard deviation value calculated at block 804. In some examples, thestandard deviation value difference may be an absolute value, which maybe calculated based on the following equation:Δσ=|σ₁−σ₂|In some examples, the standard deviation value difference calculated atblock 806 may be one of the plurality of altitude value differences ofthe first level feature.

Subsequent to block 806, the method 800 may return to block B. Referringback to FIG. 4, block B may be prior to determining a radio altimeterfailure indicator based at least in part on the first level feature atblock 410. The plurality of altitude value differences of the firstlevel feature may comprise at least one standard deviation valuedifference as described in connection with FIG. 8.

While the example as shown in FIG. 8 may illustrate generating onestandard deviation value difference, it is noted that the method 800 asdescried in FIG. 8 may be repeated by a processing circuitry on aplurality of first standard deviation values and a plurality of secondstandard deviation values to generate a plurality of standard deviationvalue differences.

For example, the processing circuitry may generate a standard deviationvalue difference for each flight. Referring to the example as shown inFIG. 3C, the processing circuitry may generate a first standarddeviation value σ₁ ¹ based on the altitude values 309 and a secondstandard deviation value σ₂ ¹ based on the altitude values 311, and maycalculate a first standard deviation value difference Δσ¹ based on σ₁ ¹and σ₂ ¹. The processing circuitry may also generate another firststandard deviation value σ₁ ² based on the altitude values 315 andanother second standard deviation value σ₂ ² based on the altitudevalues 317, and may calculate a second standard deviation valuedifference Δσ² based on σ₁ ² and σ₂ ².

In some examples, the processing circuitry may utilize the plurality ofstandard deviation value differences to determine the radio altimeterfailure indicator, details of which are described in connection with atleast FIG. 9, FIG. 10, FIG. 11, and FIG. 12.

While FIG. 5, FIG. 6, FIG. 7, and FIG. 8 may illustrate example methodsof calculating a first level feature based at least in part on thealtitude values, it is noted that the scope of the present disclosure isnot limited to these examples. In some examples, the processingcircuitry may calculate a maximum value, a minimum value, and/or thelike as the first level feature.

Referring now to FIG. 9, an example method 900 in accordance with someembodiments of the present disclosure is illustrated. In particular, theexample method 900 may illustrate example embodiments of calculating asecond level feature for determining a radio altimeter failureindicator. In some examples, the method 900 may be performed by aprocessing circuitry (for example, a processing circuitry of the dataanalytics system 115 described in connection with FIG. 1 and/or theprocessor 202 of the apparatus 200 described in connection with FIG. 2).

The method 900 may start from block C. Referring back to FIG. 4, block Cmay be subsequent to determining a first plurality of altitude values(block 404), determining a second plurality of altitude values (block406), and calculating a first level feature (block 408). As describedabove, the first level feature may comprise a plurality of altitudevalue differences, which may be calculated based on, but not limited to,the method 500 described above in connection with FIG. 5, the method 600described above in connection with FIG. 6, the method 700 describedabove in connection with FIG. 7, and/or the method 800 described abovein connection with FIG. 8.

Referring now to FIG. 9, at block 901, a processing circuitry (forexample, a processing circuitry of the data analytics system 115described in connection with FIG. 1 and/or the processor 202 of theapparatus 200 described in connection with FIG. 2) may determine aplurality of time values associated with the plurality of altitude valuedifferences.

The plurality of altitude value differences may be, for example, aplurality of mode value differences (as described above in connectionwith FIG. 5), a plurality of median value differences (as describedabove in connection with FIG. 6), a plurality of mean value differences(as described above in connection with FIG. 7), and/or a plurality ofstandard deviation value differences (as described above in connectionwith FIG. 8).

As described above, each altitude value difference may be calculatedbased on the first plurality of altitude values and the second pluralityof altitude values. Each altitude value may be associated with a timevalue that may indicate when the altitude value is recorded.

In some examples, the processing circuitry may determine the pluralityof time values from a database, including, but not limited to, theflight database 105 described above in connection with FIG. 1. Theprocessing circuitry may transmit a time value data retrieval request tothe flight database 105, and may receive time values associated with theplurality of altitude value differences.

For example, in the example as shown in FIG. 3C, the processingcircuitry may determine time values within the time value range 307 tobe associated with the altitude value difference calculated based on thealtitude values 309 and 311. As another example, the processingcircuitry may determine time values within the time value range 313 tobe associated with the altitude value difference calculated based on thealtitude values 315 and 317.

At block 903, a processing circuitry (for example, a processingcircuitry of the data analytics system 115 described in connection withFIG. 1 and/or the processor 202 of the apparatus 200 described inconnection with FIG. 2) may select a subset of altitude valuedifferences from the plurality of altitude value differences.

In some examples, the processing circuitry may select the subset ofaltitude value differences based on the corresponding time values. Forexample, the processing circuitry may select the subset of altitudevalue differences based on their corresponding time values satisfying atime value threshold.

Continuing from the above example associated with FIG. 3C, theprocessing circuitry may determine the time value threshold to be timevalues prior to a time point T. The time value range 307 may satisfy thetime value threshold, as the time value range 307 falls prior to thetime point T. Accordingly, the processing circuitry may select thealtitude value difference calculated based on the altitude values 309and 311 to be part of the subset of altitude value differences. The timevalue range 313 may not satisfy the time value threshold, as the timevalue range 313 falls subsequent to the time point T. The processingcircuitry may exclude the altitude value difference calculated based onthe altitude values 315 and 317 from the subset of altitude valuedifferences.

In some examples, a time value threshold may be a time range. Forexample, a time value may satisfy the time value threshold if it fallswithin the time range of the time value threshold.

In some examples, the processing circuitry may determine the time valuethreshold based on one or more factors. For example, the processingcircuitry may retrieve a predetermined time value threshold from adatabase. Additionally, or alternatively, the processing circuitry maydynamically determine the time value threshold. For example, theprocessing circuitry may set a time value threshold based on the modelof the radio altimeter that recorded the altitude values and/or thetraffic pattern associated with the aircraft. Additionally, oralternatively, the processing circuitry may determine the time valuethreshold based on an optimization objective value set by a user.

At block 905, a processing circuitry (for example, a processingcircuitry of the data analytics system 115 described in connection withFIG. 1 and/or the processor 202 of the apparatus 200 described inconnection with FIG. 2) may calculate a second level feature based atleast in part on the first level feature.

In some examples, the processing circuitry may calculate a maximumdifference value based on the subset of altitude value differences asthe second level feature, example details of which are described inconnection with at least FIG. 10. In some examples, the processingcircuitry may calculate a mean value based on the subset of altitudevalue differences as the second level feature, example details of whichare described in connection with at least FIG. 11. In some examples, theprocessing circuitry may calculate a standard deviation value based onthe subset of altitude value differences as the second level feature,example details of which are described in connection with at least FIG.12.

While FIG. 10, FIG. 11, and FIG. 12 illustrates example methods ofcalculating a second level feature based at least in part on the firstlevel feature, it is noted that the scope of the present disclosure isnot limited to these examples. In some examples, the processingcircuitry may calculate a minimum value, a mode value, a median valueand/or the like as the second level feature. In some examples, theprocessing circuitry may select a highest value from the subset ofaltitude value differences as the second level feature.

Referring back to FIG. 9, a processing circuitry (for example, aprocessing circuitry of the data analytics system 115 described inconnection with FIG. 1 and/or the processor 202 of the apparatus 200described in connection with FIG. 2) may determine whether the secondlevel feature satisfies a threshold at block 907.

For example, the second level feature may be a maximum difference value,and the processing circuitry may determine whether the maximumdifference value satisfies a maximum difference value threshold, exampledetails of which are described in connection with at least FIG. 10.Additionally, or alternatively, the second level feature may be a meanvalue, and the processing circuitry may determine whether the mean valuesatisfies a mean value threshold, example details of which are describedin connection with at least FIG. 11. Additionally, or alternatively, thesecond level feature may be a standard deviation value, and theprocessing circuitry may determine whether the standard deviation valuesatisfies a standard deviation value threshold, example details of whichare described in connection with at least FIG. 12.

Similar to the time value threshold described above in connection withblock 903, the processing circuitry may determine the threshold valuebased on one or more factors. For example, the processing circuitry maydetermine the threshold value based on one or more machine learningmodels, including, but not limited to, a grid search model and/or agenetic algorithm based on the subset of the altitude value differences.Additionally, or alternatively, the processing circuitry may calculate aF₁ score and/or a F-beta score based on the subset of the altitude valuedifferences, and may determine the threshold value based on the F₁ scoreand/or the F-beta score. Additionally, or alternatively, the processingcircuitry may determine the threshold value based on a precision valueassociated with the subset of the altitude value differences.Additionally, or alternatively, the processing circuitry may determinethe threshold value based on a cost matrix, which may, for example,optimize the total cost/revenue associated with the aircraft.

In some examples, the processing circuitry may generate a histogram on auser interface (via, for example but not limited to, the input/outputcircuitry 206 described above in connection with FIG. 2). In someexamples, the histogram may show the distribution of the subset ofaltitude value differences. In some examples, a user may select athreshold value based on the histogram.

In some examples, the processing circuitry may additionally oralternatively implement one or more machine learning models, such as,but not limited to, random forest or logistic regression to analyze thetrend of the subset of the altitude value differences. In some examples,the processing circuitry may generate a radio altimeter failureindicator based on the outputs from the machine learning model(s).

Referring back to FIG. 9, in response to determining that the secondlevel feature satisfies the threshold, a processing circuitry (forexample, a processing circuitry of the data analytics system 115described in connection with FIG. 1 and/or the processor 202 of theapparatus 200 described in connection with FIG. 2) may cause the radioaltimeter failure indicator to indicate no radio altimeter failure atblock 909.

For example, if the maximum difference value is calculated to be 500,and the maximum difference value threshold is set to be as less than800, the processing circuitry may determine that the maximum differencevalue satisfies the maximum difference value threshold.

In some examples, the processing circuitry may generate an electroniccommunication, such as, but not limited to, email, text message,application alert, and/or push notification, and may transmit it to aclient device (such as, but not limited to, the client devices 101A-101Ndescribed above in connection with FIG. 1) and/or cause the clientdevice to render the electronic communication. In some examples, theelectronic communication may include the radio altimeter failureindicator.

As described above, the radio altimeter failure indicator may be invarious forms. For example, the radio altimeter failure indicator may bein the form of a flag value, which may indicate whether there is or willlikely be a radio altimeter failure. In this example, the radioaltimeter failure indicator may be FALSE, and the correspondingelectronic communication may indicate that there is no radio altimeterfailure. In some examples, upon receiving the electronic communicationvia a client device, a user (for example, the aircraft maintenance team)may not take any further action.

As another example, the radio altimeter failure indicator may be in theform of a percentage value, which may indicate the likelihood that theradio altimeter may fail. For example, in response to determining thatthe second level feature satisfies the threshold, the processingcircuitry may set the radio altimeter failure indicator to 0%, and maygenerate an electronic communication accordingly, similar to thosedescribed above.

Referring back to FIG. 9, in response to determining that the secondlevel feature does not satisfy the threshold, a processing circuitry(for example, a processing circuitry of the data analytics system 115described in connection with FIG. 1 and/or the processor 202 of theapparatus 200 described in connection with FIG. 2) may cause the radioaltimeter failure indicator to indicate a radio altimeter failure atblock 911.

For example, if the maximum difference value is calculated to be 500,and the maximum difference value threshold is set to be less than 300,the processing circuitry may determine that the maximum difference valuedoes not satisfy the maximum difference value threshold.

In some examples, the processing circuitry may generate an electroniccommunication that may include the radio altimeter failure indicator,similar to those described above. In some examples, the radio altimeterfailure indicator may be in the form of a flag value (TRUE) that mayindicate there is likely a radio altimeter failure.

In some examples, the radio altimeter failure indicator may be in theform of a percentage value. The processing circuitry may calculate thepercentage value based on the value of the second level feature and/orthe threshold. For example, the processing circuitry may subtract thevalue of the second level feature from the threshold value, and maydivide the resultant subtraction by the threshold value. Continuing fromthe above example, the processing circuitry may calculate the radioaltimeter failure indicator as follows:

$\frac{\left( {500 - 300} \right)}{300} \approx {66\%}$In this example, the electronic communication may indicate that theremay be 66% likelihood that the radio altimeter may fail. Additionally,or alternatively, other methods may be implemented to calculate theradio altimeter failure indicator.

In some examples, upon receiving the electronic communication via aclient device, a user (for example, the aircraft maintenance team) mayproceed with performing maintenance operations, such as, but not limitedto, replacing the radio altimeter.

As illustrated above, the radio altimeter failure indicator may providevaluable insight on the performance of radio altimeter, and may predictfailure before it takes place.

Subsequent to block 909 and block 911, the method 900 may return toblock D. As shown in FIG. 4, block D may be prior to the method 400 endsat block 412.

Referring now to FIG. 10, FIG. 11, and FIG. 12, example methods inaccordance with some embodiments of the present disclosure areillustrated. In particular, these example methods may illustrate exampleembodiments of calculating the second level feature.

Referring now to FIG. 10, an example method 1000 in accordance with someembodiments of the present disclosure is illustrated. In particular, theexample method 1000 may illustrate example embodiments of calculating amaximum difference value as the second level feature. In some examples,the method 1000 may be performed by a processing circuitry (for example,a processing circuitry of the data analytics system 115 described inconnection with FIG. 1 and/or the processor 202 of the apparatus 200described in connection with FIG. 2).

The method 1000 may start from block E. Referring back to FIG. 9, blockE may be subsequent to selecting a subset of altitude value differences(block 903) and prior to determining whether the second level featuresatisfies a threshold (block 907).

At block 1002, a processing circuitry (for example, a processingcircuitry of the data analytics system 115 described in connection withFIG. 1 and/or the processor 202 of the apparatus 200 described inconnection with FIG. 2) may calculate a maximum difference value.

In some examples, the maximum difference value calculated at block 1002may be based on the subset of the altitude value differences determinedat block 903 of FIG. 9. The “maximum difference” of a data set may becalculated by subtracting the lowest value from the highest value in thedata set. As a non-limiting example, if the following example data setD1 represents the subset of altitude value differences:D1={50,65,44,11,85}The processing circuitry may determine that the maximum difference valueis 74, which may be calculated based on the following:85−11=74

In some examples, the processing circuitry may set the value of thesecond level feature to be the maximum difference value as calculated atblock 1002, which in turn may be used at block 907 of FIG. 9.

Referring back to FIG. 10, a processing circuitry (for example, aprocessing circuitry of the data analytics system 115 described inconnection with FIG. 1 and/or the processor 202 of the apparatus 200described in connection with FIG. 2) may determine a maximum differencevalue threshold at block 1004.

In some examples, the processing circuitry may determine the maximumdifference value threshold in accordance with methods described above inconnection with FIG. 9. In some examples, the processing circuitry mayset the value of the maximum difference value threshold as the thresholdin block 907 of FIG. 9.

Subsequent to block 1004, the method 1000 may return to block F. Asshown in FIG. 9, block F may be prior to determining whether the secondlevel feature satisfies a threshold at block 907. In some examples, theprocessing circuitry may use the maximum difference value calculated atblock 1002 and the maximum difference value threshold calculated atblock 1004 for the determination at block 907.

Referring now to FIG. 11, an example method 1100 in accordance with someembodiments of the present disclosure is illustrated. In particular, theexample method 1100 may illustrate example embodiments of calculating amean value as the second level feature. In some examples, the method1100 may be performed by a processing circuitry (for example, aprocessing circuitry of the data analytics system 115 described inconnection with FIG. 1 and/or the processor 202 of the apparatus 200described in connection with FIG. 2).

The method 1100 may start from block E. Referring back to FIG. 9, blockE may be subsequent to selecting a subset of altitude value differences(block 903) and prior to determining whether the second level featuresatisfies a threshold (block 907).

At block 1101, a processing circuitry (for example, a processingcircuitry of the data analytics system 115 described in connection withFIG. 1 and/or the processor 202 of the apparatus 200 described inconnection with FIG. 2) may calculate a mean value.

In some examples, the mean value calculated at block 1101 may be basedon the subset of the altitude value differences determined at block 903of FIG. 9. In some examples, the calculation of the mean value may besimilar to those described above in connection with FIG. 7.

Referring back to FIG. 11, a processing circuitry (for example, aprocessing circuitry of the data analytics system 115 described inconnection with FIG. 1 and/or the processor 202 of the apparatus 200described in connection with FIG. 2) may determine a mean valuethreshold at block 1103.

In some examples, the processing circuitry may determine the mean valuethreshold in accordance with the methods described above in connectionwith FIG. 9. In some examples, the processing circuitry may set the meanvalue threshold as the threshold in block 907 of FIG. 9.

Subsequent to block 1103, the method 1100 may return to block F. Asshown in FIG. 9, block F may be prior to determining whether the secondlevel feature satisfies a threshold at block 907. In some examples, theprocessing circuitry may use the mean value calculated at block 1101 andthe mean value threshold calculated at block 1103 for the determinationat block 907.

Referring now to FIG. 12, an example method 1200 in accordance with someembodiments of the present disclosure is illustrated. In particular, theexample method 1200 may illustrate example embodiments of calculating astandard deviation value as the second level feature. In some examples,the method 1200 may be performed by a processing circuitry (for example,a processing circuitry of the data analytics system 115 described inconnection with FIG. 1 and/or the processor 202 of the apparatus 200described in connection with FIG. 2).

The method 1200 may start from block E. Referring back to FIG. 9, blockE may be subsequent to selecting a subset of altitude value differences(block 903) and prior to determining whether the second level featuresatisfies a threshold (block 907).

At block 1202, a processing circuitry (for example, a processingcircuitry of the data analytics system 115 described in connection withFIG. 1 and/or the processor 202 of the apparatus 200 described inconnection with FIG. 2) may calculate a standard deviation value.

In some examples, the standard deviation value calculated at block 1202may be based on the subset of the altitude value differences determinedat block 903 of FIG. 9 by the processing circuitry. In some examples,the calculation of the standard deviation value may be similar to thosedescribed above in connection with FIG. 8.

At block 1204, a processing circuitry (for example, a processingcircuitry of the data analytics system 115 described in connection withFIG. 1 and/or the processor 202 of the apparatus 200 described inconnection with FIG. 2) may determine a standard deviation valuethreshold.

In some examples, the processing circuitry may determine the standarddeviation value threshold in accordance with the methods described abovein connection with FIG. 9. In some examples, the processing circuitrymay set the standard deviation value threshold as the threshold in block907 of FIG. 9.

Subsequent to block 1204, the method 1200 may return to block F. Asshown in FIG. 9, block F may be prior to determining whether the secondlevel feature satisfies a threshold at block 907. In some examples, theprocessing circuitry may use the standard deviation value calculated atblock 1202 and the standard deviation value threshold calculated atblock 1204 for the determination at block 907.

It is to be understood that the disclosure is not to be limited to thespecific embodiments disclosed, and that modifications and otherembodiments are intended to be included within the scope of the appendedclaims. Although specific terms are employed herein, they are used in ageneric and descriptive sense only and not for purposes of limitation,unless described otherwise.

The invention claimed is:
 1. An apparatus comprising at least oneprocessor and at least one non-transitory memory comprising programcode, wherein the at least one non-transitory memory and the programcode are configured to, with the at least one processor, cause theapparatus to at least: determine a first plurality of altitude valuesassociated with a first radio altimeter; determine a second plurality ofaltitude values associated with a second radio altimeter; calculate afirst level feature based at least in part on the first plurality ofaltitude values and the second plurality of altitude values, wherein thefirst level feature comprises a plurality of mode value differences; anddetermine a radio altimeter failure indicator based at least in part onthe first level feature.
 2. The apparatus of claim 1, wherein, whencalculating the first level feature, the at least one non-transitorymemory and the program code are configured to, with the at least oneprocessor, cause the apparatus to further: calculate a first pluralityof mode values of the first plurality of altitude values; calculate asecond plurality of mode values of the second plurality of altitudevalues; and calculate the plurality of mode value differences betweenthe first plurality of mode values and the second plurality of modevalues.
 3. The apparatus of claim 1, wherein the first radio altimeterand the second radio altimeter are associated with an aircraft, whereinthe first plurality of altitude values and the second plurality ofaltitude values are associated with the aircraft in a cruising mode. 4.The apparatus of claim 1, wherein, when determining the radio altimeterfailure indicator, the at least one non-transitory memory and theprogram code are configured to, with the at least one processor, causethe apparatus to further calculate a second level feature based at leastin part on the first level feature.
 5. The apparatus of claim 4,wherein, when calculating the second level feature, the at least onenon-transitory memory and the program code are configured to, with theat least one processor, cause the apparatus to further: determine aplurality of time values associated with the plurality of mode valuedifferences; and select a subset of mode value differences from theplurality of mode value differences, wherein corresponding time valuesassociated with the subset of mode value differences satisfy a timevalue threshold.
 6. The apparatus of claim 5, wherein the at least onenon-transitory memory and the program code are configured to, with theat least one processor, cause the apparatus to further: calculate amaximum difference value based on the subset of mode value differences;and determine whether the maximum difference value satisfies a maximumdifference value threshold.
 7. The apparatus of claim 6, wherein the atleast one non-transitory memory and the program code are configured to,with the at least one processor, cause the apparatus to further: inresponse to determining that the maximum difference value does notsatisfy the maximum difference value threshold, cause the radioaltimeter failure indicator to indicate a radio altimeter failure.
 8. Acomputer-implemented method, comprising: determining a first pluralityof altitude values associated with a first radio altimeter; determininga second plurality of altitude values associated with a second radioaltimeter; calculating a first level feature based at least in part onthe first plurality of altitude values and the second plurality ofaltitude values, wherein the first level feature comprises a pluralityof mode value differences; and determining a radio altimeter failureindicator based at least in part on the first level feature.
 9. Thecomputer-implemented method of claim 8, wherein calculating the firstlevel feature further comprises: calculating a first plurality of modevalues of the first plurality of altitude values; calculating a secondplurality of mode values of the second plurality of altitude values; andcalculating the plurality of mode value differences between the firstplurality of mode values and the second plurality of mode values. 10.The computer-implemented method of claim 8, wherein the first radioaltimeter and the second radio altimeter are associated with anaircraft, wherein the first plurality of altitude values and the secondplurality of altitude values are associated with the aircraft in acruising mode.
 11. The computer-implemented method of claim 8, whereindetermining the radio altimeter failure indicator further comprisescalculating a second level feature based at least in part on the firstlevel feature.
 12. The computer-implemented method of claim 11, whereincalculating the second level feature further comprises: determining aplurality of time values associated with the plurality of mode valuedifferences; and selecting a subset of mode value differences from theplurality of mode value differences, wherein corresponding time valuesassociated with the subset of mode value differences satisfy a timevalue threshold.
 13. The computer-implemented method of claim 12,further comprising: calculating a maximum difference value based on thesubset of mode value differences; and determining whether the maximumdifference value satisfies a maximum difference value threshold.
 14. Thecomputer-implemented method of claim 13, further comprising: in responseto determining that the maximum difference value does not satisfy themaximum difference value threshold, causing the radio altimeter failureindicator to indicate a radio altimeter failure.
 15. A computer programproduct comprising at least one non-transitory computer-readable storagemedium having computer-readable program code portions stored therein,the computer-readable program code portions comprising an executableportion configured to: determine a first plurality of altitude valuesassociated with a first radio altimeter; determine a second plurality ofaltitude values associated with a second radio altimeter; calculate afirst level feature based at least in part on the first plurality ofaltitude values and the second plurality of altitude values, wherein thefirst level feature comprises a plurality of mode value differences; anddetermine a radio altimeter failure indicator based at least in part onthe first level feature.
 16. The computer program product of claim 15,wherein the executable portion is configured to further: calculate afirst plurality of mode values of the first plurality of altitudevalues; calculate a second plurality of mode values of the secondplurality of altitude values; and calculate the plurality of mode valuedifferences between the first plurality of mode values and the secondplurality of mode values.
 17. The computer program product of claim 15,wherein the first radio altimeter and the second radio altimeter areassociated with an aircraft, wherein the first plurality of altitudevalues and the second plurality of altitude values are associated withthe aircraft in a cruising mode.
 18. The computer program product ofclaim 15, wherein, when determining the radio altimeter failureindicator, the executable portion is configured to calculate a secondlevel feature based at least in part on the first level feature.
 19. Thecomputer program product of claim 18, wherein, when calculating thesecond level feature, the executable portion is configured to: determinea plurality of time values associated with the plurality of mode valuedifferences; and select a subset of mode value differences from theplurality of mode value differences, wherein corresponding time valuesassociated with the subset of mode value differences satisfy a timevalue threshold.
 20. The computer program product of claim 19, whereinthe executable portion is configured to: calculate a maximum differencevalue based on the subset of mode value differences; and determinewhether the maximum difference value satisfies a maximum differencevalue threshold.